1. Field of the Invention
The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material which comprises a support and a heat-sensitive recording layer and a protective layer which are provided on the support, and which is excellent in transparency, glossiness, and light-fastness, and which is excellent in scratch resistance because the heat-sensitive recording material has a protective layer which is excellent in friction resistance and lubricity with respect to a heat-sensitive recording head so that adhesion of the heat-sensitive recording material to the heat-sensitive recording head or the like and deposition of foreign matters thereon can be prevented.
2. Description of the Related Art
Heat-sensitive recording has been recently developing because the device used for the heat-sensitive recording is structured simply, is highly reliable, and does not need complicated maintenance. As a heat-sensitive recording material, conventionally, compounds obtained through the reaction of an electron donative colorless dye and an electron acceptive compound, and compounds obtained through the reaction of a diazonium salt compound and a coupler are widely known.
In recent years, in order to improve properties including color developing density and color developing sensitivity, fastness of a color developer and the like in heat-sensitive recording materials, extensive studies have been carried out. However, when a heat-sensitive recording material is exposed to sunlight or displayed on walls at offices or the like for a long period of time, there have been drawbacks in that background portions of the material become colored through irradiation of light, and image areas may become discolored or faded. In order to limit the discoloring or fading of image areas, various methods have been proposed. However, these methods fail to provide sufficient results.
On the other hand, in many fields such as facsimiles, printers, labels, and the like, demand for a heat-sensitive recording system is increasing. Accordingly, there is a great demand for a heat-sensitive recording material of higher performance. Image recording of the heat-sensitive recording material is carried out by a heat-sensitive recording head through imagewise heating. In order to print an image on a heat-sensitive recording material in a smooth manner without printing failures and obtain a high quality image which is excellent in glossiness, it is desired to decrease kinetic friction between the heat-sensitive recording material and the heat-sensitive recording head to a certain value or less.
Conventionally, in order to impart friction resistance and lubricity to a heat-sensitive recording material, waxes (e.g., zinc stearic acid or the like), matifying agents, pigments, and the like have been used. However, such means as described above fail to sufficiently provide improvements in friction resistance and lubricity. In addition, if the heat-sensitive recording material is a reflecting material, transparency and glossiness thereof decrease (if the heat-sensitive recording material is a transparent material, the haze degree thereof increases). Further, there have been drawbacks in that these compounds become fused to a heat-sensitive recording head, a printed surface, and the like so that failures such as deposition of foreign matters, unevenness in glossiness, and the like are caused to the heat-sensitive recording material.